User plane location services over session initiation protocol (sip)

ABSTRACT

A method and mechanism to allow a location server to initiate a user plane location service (e.g., SUPL defined by OMA) procedure to a user plane enabled device via Instant Messaging, or alternatively, via an existing SIP session if a multimedia session is already established. The location request is signaled to the user plane enabled device via a SIP INFO message. The location request uses SIP messaging to overcome firewall and other network security issues. Location using SUPL over SIP may be provided about a caller making an E911 emergency call. An Instant Message may be sent to the user plane enabled device, e.g., a VoIP wireless phone.

The present application claims priority from U.S. ProvisionalApplication No. 60/861,267, entitled “User Plane Location Service overSession Initiation Protocol (SIP)”, filed Nov. 28, 2006, the entirety ofwhich is expressly incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to wireless and long distance carriers,Internet Service Providers (ISPs), and information content deliveryservices/providers and long distance carriers. More particularly, itrelates to location services for the wireless industry.

2. Background of Related Art

Location information regarding subscribers is becoming increasinglyavailable in a wireless network. Location information relates toabsolute coordinates of a wireless device.

FIG. 4 shows a conventional LoCation Services (LCS) request.

In particular, as shown in FIG. 4, a location server 106 requestslocation information regarding a particular mobile subscriber (MS) froma core network node, e.g., from a Mobile Switch Center (MSC) 110.Requested information regarding a particular wireless device (MS) mayinclude, e.g., attach, detach, and location area update. The locationserver 106 may also request information regarding the wireless devicesuch as attach, detach and/or location area update from a Packet DataNode (e.g., SGSN, GGSN, or PDSN), or help the device calculate x/ydirection. Typically, location information regarding a particularwireless device is requested of a home location register (HLR).

As shown in step 1 of FIG. 4, a locations services client 104 sends amessage to a location server 106.

In step 2, the location server 106 sends a Provide Subscriber Infomessage to a Home Location Register 108, requesting subscriberinformation regarding a particular subscriber.

In step 3, the carrier's Home Location Register (HLR) 108 provides thesubscriber information for the requested subscriber back to the locationserver 106.

In step 4, location information regarding the requested subscriber isrequested to either an MSC or Packet Data node 110. The MSC or PacketData Node preferably provides precise location information using, e.g.,a global positioning satellite (GPS), triangulation techniques, or otherrelevant locating technology, or helps the device calculate X/Ydirection.

In step 5, the location request is forwarded to the Radio Access Network(RAN) 112 if needed.

In step 6, precise, updated location information regarding the requestedsubscriber is sent to the location server (LS) 106.

In step 7, an ultimate response to the original location request is sentto the LCS client 104 that initially requested the location information.

Secure User Plane for Location (SUPL) is a standards-based protocol thathas been developed to allow a mobile handset client to communicate witha location server, e.g., as shown in step 1 of FIG. 4. The SUPLspecification is defined by the Open Mobile Alliance (OMA) standardsworking group. Refer to OMA Secure User Plane Location Architecturedocument, OMA-AD-SUPL-V1_(—)0-20060127-C for more details on OMA SUPLcall flows; and OMA User Plane Location Protocol document,OMA-TS-ULP-V1_(—)0-20060127-C. The OMA SUPL Version 1 specifies twobasic types call flows: (1) a SUPL network initiated (NI) call flow, and(2) a SUPL set initiated (SI) call flow. According to the SUPL standard,a session ID has a unique value consisting of server and handsetportions.

FIG. 5 shows typical OMA mobile terminated call flow for a SUPL locationrequest initiated by a SUPL agent.

In particular, as shown in FIG. 5, messages are passed between a SUPLagent 802 residing in the network, a sat reference server 804, a SUPLserver 806, a PPG 808, and a SUPL terminal (SET) 812.

The SUPL server (or SUPL location platform (SLP)) 806 comprises a SUPLlocation center (SLC) and SUPL positioning center (SPC). A mobile deviceis generalized in FIG. 5 as a SUPL enabled terminal (SET) 812. The SLCcoordinates operations of SUPL communications in the network, andcontrols the SPC component. The SPC Provides global positioning system(GPS) assistance data to the SUPL enabled terminal (SET) 812, andperforms precise position calculation of a SET 812.

Network initiated location requests 820 arrive at the SUPL server 806via an MLP interface. The SUPL server 806 processing this networkinitiated request is required to send a trigger message (SUPL INITmessage) 822 to the SET 812 for validating and initiating a SUPLpositioning session 828. The trigger message 822 is sent to the SET 812as a push message 824 from the PPG 808 (or as an SMS message from anSMSC/MC). At that point, the SET 812 needs to establish a secure TCP/IPconnection to the SUPL server 806 to respond to the SUPL positioningrequest.

For network initiated end-to-end IP based location services, when alocation server needs to find out contact information (e.g. an IPaddress) of a given target, the location server sends a trigger to thetarget to allow the target to establish a session with the locationserver. Conventional IP based user plane location services (e.g., OMASUPL) are built upon WAP Push/SMS messaging and TCP as a transportprotocol for initiating a mobile terminating positioning procedure.

There are some scenarios where conventional use of User Plane LocationServices does not work or does not work well.

For example, in one scenario where a target device has Internet accessvia, e.g. WLAN, LAN, or DSL, it may not be possible for the locationserver to initiate location by use of an SMS, WAP Push. This isparticularly true if the location server cannot determine the IP addressof the target device, and the network to which the target deviceattaches does not support correct inter-working with SMS or WAP Pushmessaging.

A second example relates to Voice over IP (VoIP) based emergency calling(there are some variances in the wireless industry, e.g., IMS emergencyin the 3GPP standard and MMD emergency in the 3GPP2 standard, referredto generally as a SIP call by the IETF.) This scenario depicts anemergency call which has already established a SIP session with theserving network. During the emergency call, the appropriate PublicSafety Answering Point (PSAP) may require updated location informationrelating to the emergency caller.

The present inventors appreciate that the existing mechanism of usingWAP Push/SMS messaging may not be efficient and reliable, as WAPPush/SMS messaging is built upon store-and-forward mechanisms. In otherwords, there is no guarantee that the trigger of a location servicerequest will be delivered to a target before the emergency call ends.

SUMMARY OF THE INVENTION

The present invention introduces a method and a mechanism that allows alocation server to initiate a user plane location service (e.g., SUPL)procedure to a user plane enabled device via Instant Messaging, oralternatively, via an existing SIP session if a multimedia session isalready established.

In accordance with one aspect of the invention, a method and apparatusfor obtaining a location of a caller comprises initiating a user planelocation service procedure. If a session initiation protocol (SIP)session already exists, a location request is signaled to a user planeenabled caller device via session initiation protocol (SIP).

A method and apparatus for obtaining a location of a caller inaccordance with another aspect of the invention comprises determining ifa multimedia session is already established with a caller. If amultimedia session is already established with the caller, updatedlocation information of the caller is obtained via an existing sessioninitiation protocol (SIP) session.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of the present invention will become apparent tothose skilled in the art from the following description with referenceto the drawings, in which:

FIG. 1 illustrates a high level message flow where User Plane LocationService uses SIP based signaling as the transport, in accordance withthe principles of the present invention.

FIG. 2 illustrates a variance of the User Plane Location Serviceprocedure where a location server acts as a watcher of the locationservice and initiates a location retrieval procedure only when thetarget device is on-line, in accordance with the principles of thepresent invention.

FIG. 3 illustrates another use case where the solution of User PlaneLocation Service over SIP is used to retrieve the updated location of aVoIP emergency caller, in accordance with the principles of the presentinvention.

FIG. 4 shows a conventional LoCation Services (LCS) request.

FIG. 5 shows typical OMA mobile terminated call flow for a SUPL locationrequest initiated by a SUPL agent.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The present invention introduces a method and a mechanism that allows alocation server to initiate the user plane location service procedure toa user plane enabled device via Instant Messaging, or alternatively, viaan existing SIP session if a multimedia session is already established.

Session Initiation Protocol (SIP) is an Internet Engineering Task Force(IETF) standard protocol for initiating an interactive user session thatinvolves multimedia elements such as video, voice, chat, gaming, virtualreality, etc. SIP is specified in IETF Request for Comments (RFC) 3261(replacing 2543). Like HTTP or SMTP, SIP works in the application layerof the open systems interconnection (OSI) communications model. SIP canalso be used to invite participants to sessions that do not necessarilyinvolve the initiator. Because SIP supports name mapping and redirectionservices, it makes it possible for users to initiate and receivecommunications and services from any location, and for networks toidentify the users wherever they are. SIP is a request-response protocoldealing with requests from clients and responses from servers.Participants are identified by SIP universal resource locators (URLs).Requests can be sent through any transport protocol, such as UDP, SCTP,or TCP. SIP determines the end system to be used for the session, thecommunication media and media partners, and the called party's desire toengage in the communication. Once these are assured, SIP establishescall parameters at either end of the communication, and handles calltransfer and termination.

FIG. 1 illustrates a high level message flow where User Plane LocationService uses SIP based signaling as the transport, in accordance withthe principles of the present invention.

In particular, as shown in FIG. 1, the general service description isdescribed as follows:

In step 1 of FIG. 1, a location service enabled device 200 hassuccessfully granted Internet access from an Internet Service AccessProvider 202, via either fixed lined access (e.g., dial-up, DSL, cableor LAN) or wireless access using one of the following (but not limited):Wireless LAN (MAN) that is built based on IEEE 802.11x; Wirelesspersonal area network (WPAN) that is built based on IEEE 802.15 (alsoreferred to as BLUETOOTH™); Worldwide Interoperability for MicrowaveAccess (WiMAX) or Wireless metropolitan area network (WMAN), which isbuilt based on IEEE 802.16; Third generation (3G) packet data accesstechnologies based on UMTS or 1xEVDO, or the enhanced technologies, e.g.High Speed Downlink Packet Access (HSDPA); packet data access oversatellite; or High speed packet data access over speed point-to-pointoptical link, e.g. built based on IEEE 802.17.

The location service enabled device 200 then initiates the necessaryregistration of presence service per RFC2778, 2779 and 3856. Uponregistration to the presence service, the device contact informationincluding networking information (e.g. IP address) etc. is stored in apresence server 204.

In step 2, a request for location information of the location serviceenabled device 200 is generated by a location service provider 206. Thelocation request may be generated by an application in the network thatuses the location information, e.g., a weather report based on location;or by an application that resides in the end user terminal.

In step 3, the corresponding location service client 208 sends alocation request to a location server 210 for the target device 200specified by one of the following identifiers, together with othercriteria: MSISDN; IMSI; MSN; MIN; IP address; SIP URI; TEL URI; or XMPPURI.

In step 4, upon receiving the location request, the location server 210examines the identifier(s) of the target device 200 and determines thatthe target device 200 is not in a conventional mobile network (e.g.,packet data enabled cellular network). The location server 210 theninitiates an Instant Message containing the information needed totrigger the user plane location service procedure to thepresence/Instant Message server 204. The location server 210 mayretrieve the SIP URI, XMPP URI or TEL URI of the target device 200 basedon the received identifier other than SIP URI, XMPP URI or TEL URI fromother network entities, e.g., HLR/HSS in the cellular networks.

In step 5, based on the registration information, the presence/InstantMessage server 204 forwards the Instant Message to the target device 200via SIP. In the disclosed embodiments, the Instant Message can be sentover the existing SIP session if there is an existing SIP sessionestablished between the target device 200 and the presence/InstantMessage server 204.

In step 6, upon receipt of the Instant Message containing informationnecessary for trigging the User Plane Location Service procedure, thetarget device 200 initiates a User Plane Location Service session withthe location server 210. The User Plane Location Service signaling caneither use standard TCP/IP or UDP/IP, or use standard SIP signaling asthe transport. Using SIP signaling as the transport has some advantagewhen there are security entities (e.g. firewalls) involved in thenetworks, where direct IP connectivity with certain ports is notaccessible. Upon completion of the User Plane Location Serviceprocedure, the location server 210 retrieves a location fix of thetarget device 200.

In step 7, the location server 210 returns the retrieved location fix tothe location service client 208.

In step 8, the location service client 208 sends the locationinformation back to the location service application.

FIG. 2 illustrates a variance of the User Plane Location Serviceprocedure where a location server 210 acts as a watcher of the PresenceService 210 and initiates a location retrieval procedure only when thetarget device 200 is on-line, in accordance with the principles of thepresent invention.

The procedure shown and described with respect to FIG. 2 may beimplemented as the primary procedure for a User Plane Location Service.Alternatively, it can be implemented as a fallback procedure to the callflow shown and described with respect to FIG. 1.

The general service description shown in FIG. 2 is described as follows:

In step 1, a request for location information of the location serviceenabled device 200 is generated by a location service provider 206. Thelocation request may be generated by an application in the network thatuses the location information, e.g., a weather report based on location;or by an application that resides in the end user terminal.

In step 2, the corresponding location service client 208 sends alocation request to a location server 210 for the target device 200specified by one of the following identifiers, together with othercriteria: MSISDN; IMSI; MSN; MIN; IP address; SIP URI; TEL URI; or XMPPURI.

In step 3, upon receipt of the location request message, the locationserver 210 examines the identifier(s) of the target device 200 anddetermines that the target device 200 is not being served by aconventional mobile network (e.g., packet data enabled cellularnetwork). The location server 210 then initiates a request to thepresence/Instant Message server 204, to obtain presence relatedinformation of the target device 200. Alternatively the location server210 may try a conventional mobile network path using the existing WAPPush/SMS mechanism and the inventive mechanisms disclosed herein eitherin parallel or in an order. For example, the target device supportsmultiple access technologies and networks.

In step 4, the target device 200 becomes available and sends a statusupdate to the presence/Instant Message server 204.

In step 5, the presence/Instant Message server 204 sends a notificationcontaining the contact information for the target device 200. Thecontact information may include, e.g., an IP address of the targetdevice 200.

In step 6, optionally, the location server 210 initiates an InstantMessage containing the information needed to trigger the user planelocation service procedure to the presence/Instant Message server 204.

In step 7, based on the registration information, the presence/InstantMessage server 204 forwards the Instant Message to the target device 200via SIP. In the disclosed embodiments, the Instant Message can be sentover the existing SIP session if there is an existing

SIP session established between the target device 200 and thepresence/Instant Message server 204.

In step 8, upon receipt of the Instant Message containing informationnecessary for trigging the User Plane Location Service procedure, thetarget device 200 initiates a User Plane Location Service session withthe location server 210. The User Plane Location Service signaling caneither use standard TCP/IP or UDP/IP, or use standard SIP signaling asthe transport. Using SIP signaling as the transport has some advantagewhen there are security entities (e.g. firewalls) involved in thenetworks, where direct IP connectivity with certain ports is notaccessible. Upon completion of the User Plane Location Serviceprocedure, the location server 210 retrieves a location fix of thetarget device 200.

In step 9, the location server 210 returns the retrieved location fix tothe location service client 208.

In step 10, the location service client 208 sends the locationinformation back to the location service application.

FIG. 3 illustrates another use case where a User Plane Location Serviceover SIP is used to retrieve updated location information regarding avoice over Internet protocol (VoIP) emergency caller, in accordance withthe principles of the present invention.

The general service description shown in FIG. 3 is described as follows:

In step 1 of FIG. 3, a VoIP based emergency call is initiated from aVoIP terminal 300, via either fixed line access (e.g., dial-up, digitalsubscriber loop (DSL), cable or local area network (LAN)), or wirelessaccess using one of the following (but not limited): Wireless LAN (WLAN)that is built based on IEEE 802.11x; Wireless personal area network(WPAN) that is built based on IEEE 802.15 (also referred to asBLUETOOTH™); Worldwide Interoperability for Microwave Access (WiMAX) orWireless metropolitan area network (WMAN), which is built based on IEEE802.16; Third generation (3G) packet data access technologies based onUMTS or 1xEVDO, or the enhanced technologies, e.g. High Speed DownlinkPacket Access (HSDPA); packet data access over satellite; or High speedpacket data access over speed point-to-point optical link, e.g. builtbased on IEEE 802.17.

The VoIP emergency call is established with an appropriate Public SafetyAnswering Point (PSAP) 310 through the public switched telephone network(PSTN) 320, selective router network 330, or direct session InternetProtocol (SIP) based network from the emergency 911 call server 304.

In step 2, during the VoIP emergency call, the PSAP 310 requests anupdated location of the VoIP emergency caller 300.

In step 3, if the location server 210 is in the SIP call signaling path,it initiates a trigger message using the User Plane Location Serviceembedded in a SIP INFO message to the E911 call server 304.

In step 4, the SIP INFO message is forwarded to the VoIP emergencycaller 300.

In step 5, upon receipt of the trigger message using a User PlaneLocation Service, the VoIP terminal 300 from which the VoIP emergencycall was initiated starts a User Plane Location Service procedure withthe location server 306.

In step 6, the location server 306 returns retrieved locationinformation to the PSAP 310.

While the invention has been described with reference to the exemplaryembodiments thereof, those skilled in the art will be able to makevarious modifications to the described embodiments of the inventionwithout departing from the true spirit and scope of the invention.

1-24. (canceled)
 25. A method for obtaining a location of a subscriberwireless device, comprising: signaling, at said location server, aSecure User Plane for Location (SUPL) location request via an existingmultimedia session initiation protocol (SIP) session established betweensaid location server and a target wireless device via a physicalpresence server; and retrieving, via a user plane location servicesession, location information associated with said target wirelessdevice.
 26. A method for obtaining a location of a subscriber wirelessdevice according to claim 25, further comprising: initiating said userplane location service session via Extensible Messaging and PresenceProtocol (XMPP) protocol.
 27. The method for obtaining a location of asubscriber wireless device according to claim 25, wherein: said SUPLlocation request is signaled to said target wireless device via a SIPINFO message.
 28. The method for obtaining a location of a subscriberwireless device according to claim 25, wherein said signaling, at saidlocation server, comprises: transmitting a SIP message as saidsignaling, to overcome network security.
 29. The method for obtaining alocation of a subscriber wireless device according to claim 28, whereinsaid network security comprises: a firewall.
 30. The method forobtaining a location of a subscriber wireless device according to claim25, further comprising: receiving an emergency call from said targetwireless device via Voice over Internet Protocol (VoIP).
 31. The methodfor obtaining a location of a subscriber wireless device according toclaim 25, wherein said target wireless device comprises: a voice overInternet Protocol (VoIP) phone.
 32. The method for obtaining a locationof a subscriber wireless device according to claim 25, wherein: saiduser plane location service session complies with a secure user planefor location (SUPL) standard defined by Open Mobile AllianceOMA-TS-ULP-V1_(—)0-20060127-C.